This invention relates to a spray gun apparatus for spraying paint and the like. The invention particularly relates to a safety apparatus for guarding the region near the paint spray orifice and for disabling the spray gun trigger, and to a spray actuating mechanism which operates in cooperation with the safety apparatus.
In the field of painting, and particularly paint spraying, there has been developed apparatus and techniques for spraying paints under high hydraulic pressures. The apparatus usually embodies a pistol-shaped spray gun having a trigger which controllably actuates a valve for admitting paint into a chamber and emitting it from the chamber through an orifice. Because of the extremely high hydraulic pressures utilized in this type of spray gun the emitted paint travels at high particle velocities which are sufficient to penetrate the skin if one comes within several inches of the paint spray orifice. Beyond this "critical zone" of danger the paint particle velocities are reduced to a point where they are not sufficient for skin penetration and are therefore not dangerous. It is therefore important to guard against close personal contact with the region near the paint spray orifice, and operators are typically warned of this danger through various means. Apparatus has been developed to provide a guard around the region of the paint spray orifice in order to prevent a person from coming into contact with this region. For example, in U.S. patent application Ser. No. 532,021, filed Dec. 12, 1974, and owned by the same assignee as the current invention, a novel guard is described which accomplishes the purpose of protecting against personal contact with the region around the paint spray orifice.
Another approach to preventing inadvertent spraying is to design a safety guard mechanism for disabling the paint spray gun trigger whenever the gun is not actually being used for spraying. U.S. patent application Ser. No. 450,927, filed Mar. 13, 1974, now U.S. Pat. No. 3,913,844, and owned by the same assignee as the present invention describes a trigger disabling feature which is but one of a number of approaches to solving this problem.
Improved safety features of the general class described above have been incorporated into the basic spray gun operating mechanism which includes a trigger actuator and a paint spray valve mechanism. As hereinbefore stated, the valve operates to open a passage between the pressurized paint chamber within the spray gun and the paint spray orifice. In such a spray apparatus, the pressurized paint line is typically attached to the spray gun, usually to its handle, and internal passages provide a conduit for the pressurized paint to travel to the paint chamber openable by the valve.